Blue Lobster in a Community Tank

[fishfreak5]

I found one in my book you could have used but I dont think you want a 20inch shark,that would probably ecxeed your limits...

 

[Bluestman]

Thanks for all the suggestions for the alage eater type fish but I think I'm going to leave it for a while, and yes indeed 20 inch shark would be seriously too big lol. I think once the java moss takes hold in my tank the algae will be significantly reduced.

Well I added a couple of guppies on Tuesday (27.01.09) to see how they would get on, they were OK for the first day then I noticed one of them was kind of lying on its side in the tank. There was no visible damage so it hadn't been attacked but it was very lethargic. Next time I checked, a few hours later, the lobster had eaten most of its tail. Unfortunately I wasn't around when the guppy was killed/died so it's hard to say whether the lobster has killed it or scavenged it. He ate the guppy from the tail up. He got around half way through it and then stashed it in his "den". Later that evening he brought out the carcass and ate some more. I observed his arch enemy, the apple snail , stealing the rest of the guppy from him which was quite funny. He then snatched it back with his pincers and allowed it to "float until it was caught on the plants. He literally held it up against the plant with his pincer so that when it floated it was above the bottom of the tank and out of the snails reach. It seemed deliberate but I guess it could have been just pure luck.
There is 1 guppy left, let's see how it gets on. The danios and the mollys don't seem to be bothered by him at all, the mollys do seem to tease him when he is outside of his den and he is nervous of them because they are bigger. He measures around 3 1/2" at the moment but I believe they can get up to 8". So with time I guess the situation will be reversed. I must say I do feel a bit like a teacher at the moment, every time I look at the tank I do a registration

His den is now apparently complete. I have a long stone (30cm long, 5cm wide and 4 cm thick) on an angle resting on three stones so there is a triangular gap beneath it that is around 10cm at its' highest point. This gap is now almost filled with a mound of stones. There is just a small slit now that he uses to get in and out. He has dug all the way to the bottom of the tank inside the den and now spends most of his time lying there underneath my fake plants and airlines. He mostly eats in the open but will carry anything large into his den for storage and then drag it out again later to finish it off.

 

[marchmaxima]

fascinating and you've written a very good description of what's going on.

 

[sprout18]

This is so interesting to read! Thank you so much for doing this. It makes me more and more fascinated with home aquariums.

 

[Bluestman]

Thanks for all your kind words

I have been away for a few days, it was only supposed to be two nights but due to the British transport system falling to pieces because of a couple of inches of snow I was away for 4 days . I stayed an extra nights because of the weather then it took me 24 hours to travel 200 miles. I've never travelled for so long before without getting on a plane

Before I left I fished the second dead guppy out. I was there to see it die so I now know that the other one wasn't attacked, just scavenged when weak/dead. No idea why they died, I have tested the water and there is no problem and all the other fish are fine so I can only guess that there was something wrong with the guppies when I got them. It seems one of the guppies was female and gave birth before she died, there are 2 tiny guppies darting around my plants. So all is not lost.

Since I've been away I think he has moulted again. I'm convinced he is bigger by about 1/2". his antenna have definitely grown from around 4" to nearer 8". I will try and get more photos on as soon as possible. I need about 3 days sleep at the moment.

Something which I have intended to mention before is the way he filter feeds. I've tried to find the words to explain it but it is very difficult so bear with me on this. He sits in the current normally under the filter facing towards the current so that the stream is passing under his body from front to back. He holds his tail so that the water hits it and moves it back towards his maxillipeds (mouth parts) I guess so he gets 2 shots at filtering the same water. He seems to direct the flow of water underneath him by raising and lowering his tail to decrease and increase the flow. It could be he's just using his tail along with his swimmerets to stay in the same position but he tends to hold onto the floor of the tank with his main pincers it's hard to say.

I will update with pics over the next few days

 

[gzeiger]

That's not feeding behavior, it's breathing.

 

[Bluestman]

Ah so now I know, thank you, the reason I thought it was feeding is because he is constantly using his walking legs to move food to his mouth whilst he is doing this.

 

[strokinbyeu]

great thread. i just added a electric blue crayfish to my tank. i also have a crab and 8 other fish including a pecosomis. ond he dosnt bother any of them. he has walked over top the pecosomis and didnt atempt to eat or pinch it. he really likes turtle pellets. mine is blue as can be but when he was removed from the tank at the fish store he turned a dark red/brown color for a few hours till i got him in my tank and almost im mins he turned back to his bright blue color

 

[Bluestman]

Sorry for the delay in posting, just haven't had the time lately. Couple of things to report

Firstly there is no such thing as a fish that's too fast for the lobster to catch. I added 6 neon tetras which I assumed would be far too quick for him to catch. I now have 5 tetras so I'm guessing one became lobster lunch. He has also eaten a Danio, I knew it was the lobster when half a fish started floating around the tank. I netted it and offered it to him with tweezers, he snatched the remains right back and scurried to his cave to finish it off.
I moved my filter into the corner of the tank right next to his hide and the fish congregated there and they were an easy catch for him. So I think I caused their demise. Since moving the filter back to where it was in the centre of the side of the tank there have been no more losses. Although he is now actively hunting fish. Except for the mollies who seem to tease him relentlessly then swim away when he gets annoyed.

Secondly he appears to be an enthusiastic gardener. I put quite a bit of Java moss and Java Fern in the tank which initially he ignored however the Java moss was soon collected and placed in his den and then slowly eaten. and the Java fern was well and truly pruned. Causing me to have to do a massive cleanup of the tank as the filter became clogged with the debris. I wasn't sure whether to just move the Java fern to another part of the tank, away from his hide so I placed it on a ledge leaving the roots of the plants dangling in the water overnight. He promptly climbed up the filter, dragged them all back into the tank and started clipping them again. Another cleaning up job for me. I think I will just stick to plastic plants for now lol. Although he created the mess he is currently roaming around the tank finding bits of leaves that I have missed and eating them.

Before getting the lobster I had a bit of a snail explosion, one or two must have sneaked in with a plant and soon I could see dozens of them around the tank. This seems to have been sorted out, whether the lobster ate them I'm not sure but it is a possibility as I found lots of empty shells around. After the initial aggression with the apple snail. He seems to have reached a truce with the apple snail, he no longer attacks it and the snail will quite happily sit there while the lobster cleans algae off him which is strange to watch.
Other than the above, it seems he's ready to moult again, he literally looks like he's bursting at the seams. Thanks for the advice about calcium, I have added some crushed coral to the tank and hopefully that will suffice if he does moult soon which seems to be the case it means he is moulting on a monthly basis. He has what look like hairs growing on his pincers which are apparently a harmless parasite. On reading it seems I can wipe these off with a cotton bud but they will just grow back so I will leave them for now.
General behaviour wise, I expected him to be in his cave all day and only venture out at night but he seems to be active all the time, constantly moving about the tank cleaning or "standing guard" outside his cave. When I feed the fish flake food he rushes out and stands in front of the filter grabbing any flakes that come within reach. He claims any sinking food, shrimp pellets and bloodworm pellets and they are stashed inside his cave and then eaten at his leisure

Pictures in following post

 

[Bluestman]

Apologies for the colour of these pics, one of my mollies has got a fungus issue so I have treated the tank which has turned the water bright green.

Taking food back to his cave

I have lots of random stones in my tank, bits of glass from the beach and crystals etc. He likes to tidy them up into one pile. The black one in this picture was originally at the other end of the tank so he has just carried it a distance of around four feet.

Lobster with his "friend" the apple snail

 

[GIES2525]

As i mentioned before, i also have a blue Lobster. Ive noticed yours still hasnt changed color at all in to blue. I wonder why that is? I also noticed your lil guy has molted multiple times. Ive had mine for probably four months now, and he hasnt done this once yet. Unless i didnt see it take place, but it sounds like its a few day process and i check my tank daily with no signs. So im not sure whats taking my guy so long to do this.
But awesome thread, i check for updates all the time on your lil guy, to see if hes eating as many of your fish as mine is eating my fish! lol

 

[Bluestman]

As i mentioned before, i also have a blue Lobster. Ive noticed yours still hasnt changed color at all in to blue. I wonder why that is? I also noticed your lil guy has molted multiple times. Ive had mine for probably four months now, and he hasnt done this once yet. Unless i didnt see it take place, but it sounds like its a few day process and i check my tank daily with no signs. So im not sure whats taking my guy so long to do this.
But awesome thread, i check for updates all the time on your lil guy, to see if hes eating as many of your fish as mine is eating my fish! lol

All the literature I have read states that they turn blue with age I guess mine is about 5-6months old now so still a relative youngster. I have only actually witnessed him moulting once, I went away for a few days about a month later and he did seem to have grown considerably which suggested a moult while I was away. They moult their shells in order to grow and the younger they are the more often they would need to. As yours is fully blue it is probably older and nearer to fully grown so would not need to moult as often. Believe it or not the moult I witnessed was all done in around 6-12 hours. I spotted the discarded shell and within 6 hours it had eaten it all so it may be that yours has moulted and eaten the discarded shell all while you were asleep lol. The new shell is normally soft and takes a few days to harden so during that time you may find the lobster is a lot less active and spends time hiding away as they are more vulnerable until the shell has completed hardening.

 

[gzeiger]

It's greatly to their advantage to minimize the time spent with a soft shell. It hardens up most of the way within hours of the molt, though it does continue to harden afterward for some time.

They molt much more often when they are young since they're growing faster. It's not uncommon to see weekly molts with a very small one, while a big one may go months.

 

[strokinbyeu]

my electric blue crayfish consumed his first fish from my tank yesterday. when i was fedding yesterday morning i found him hiding in a cave he made under a log with my plecostamus about half eatin. i feel bad for the plecostamus but i think the crayfish is about to moult so hes lookin for a lil more nutriants.

 

[authorize]

Awesome pics, Bluestman! I was thinking of doing a tank and getting 1 or 2 crawfishes/crayfishes, but have read about those guys having fishes for lunch and dinner. Have thought about getting a tank divider, but not sure if it's worth it.

 

[gzeiger]

They like to have their tank bottom space. Dividers aren't the best way to do it. There are fish that never venture near the bottom though, so are not easy targets. It also helps to have a night light near the tank, since the fish are most vulnerable right when lights go out and they are effectively blind while the crayfish who has been hiding all day and is habitually nocturnal is mostly adjusted to seeing in the dark already.

 

[jay942942]

Never house a lobster with fish. Most small fish will get eaten by/harassed by the lobster. Fish larger than the lobster will also start getting harrased and for that reason may start attacking the lobster. Lobsters should live in species tanks.

 

[BillD]

Some misinformation has gone unchallenged here. Firstly, that species will get far larger than 4 inches, and possibly as much as 11 inches. The speciman in the photos appears to be a female, since their is no orange on the claws, although it may not be showing yet. They are tropical crayfish and need warm water of around 80F to prosper. They like to chew wood, and need to have a tight lid on the tank. When they get larger they are very strong and can move a lid out of the way. An airline is all they need to get to the top of the tank and shove the lid aside. I lost my female when she was about 7 inches long and escaped by moving the lid and I didn't find her for several weeks after she was long dried up.
They are stealthy hunters when they get larger and become expert on preying on fish. The one downside to them is they are rather short lived in that their life expectancy is only around 2 years. If well fed and kept in clean conditions they will get quite large very quickly. They are sensitive to nitrate so require frequent regular water changes of a large nature (dependant on tank size and bioload).
They definitely get more colourful as they get older and with every molt they get darker. The females seem to have more pink and purple on them, and of course they don't get the orange on the claws. it is absolutely essential they never come in contact with any North American species of crayfish which carry a virus that is lethal to Cherax species. Best not to have any in the same building.
Good luck with this one Bluestman.

 

[strokinbyeu]

breeding

i was wondering if anybody had any info on breeding blue lobsters.

 

[gzeiger]

You need a male and a female and put them in a tank. They should take care of the rest. Note the babies are very small and are a favored food for many fish.